The present invention relates to a novel nucleic acid-containing glycoprotein having an activity for inhibiting the growth of malignant tumor cells and a lectin-like activity.
The term "lectin-like activity" herein mentioned is used for describing generally cancer cell-specific cell-agglutinating activity and blast-transforming activity to lymphocytes, all of which are inherent in substances referred to as lecitin, and non-specific inhibitory function on antigen-specific erythrocyte agglutination, affinity to the surface of lymphocyte and activity to macrophage.
Formerly, the present inventors prepared a substance having an activity for inhibiting the growth of malignant tumor cells by extracting a basidiomycetous fungus belonging to the genus Coriolus with hot water or an aqueous alkali solution, and after isolating a nitrogen-containing polysaccharide from the extract, they confirmed that the nitrogen-containing polysaccharide is an active ingredient of the substance (refer to U.S. Pat. Nos. 4,051,314 and 4,202,969).
As a result of studying further the constituents of the substance extracted from the fungus, the present inventors have found a novel nucleic acid-containing glycoprotein having a higher weight ratio of the protein moiety thereof to the saccharide moiety thereof and a specific mode of bonding between the saccharide moiety and the protein moiety, and showing lectin-like physiological activities as well as an activity for inhibiting the growth of malignant tumor cells in mammals. And, the present inventors have found a novel nucleic acid-containing glycoprotein being quite different from the conventional nitrogen-containing polysaccharides and have attained the present invention.